University of Khartoum

Cosmic Acceleration with a Positive Cosmological Constant

Cosmic Acceleration with a Positive Cosmological Constant

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Title: Cosmic Acceleration with a Positive Cosmological Constant
Author: Arbab, Arbab I.
Abstract: We have considered a cosmological model with a phenomenological model for the cosmological constant of the form = β ¨R R where β is a constant. For age an parameter consistent with observational data, the universe must be accelerating in the presence of a positive cosmological constant. The minimum age of the universe is H −1 0 , where H0 is the present Hubble constant. The cosmological constant is found to decrease as t −2. Allowing the gravitational constant to change with time leads to an ever-increasing gravitational constant at the present epoch. In the presence of a viscous fluid this decay law for is equivalent to the one with = 3αH2 (α = const) provided α = β 3(β−2). The inflationary solution obtained from this model is that of the de Sitter type
URI: http://khartoumspace.uofk.edu/handle/123456789/17626
Date: 2015-12-14


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